The Physical Vapor Deposition (hereinafter referred to as PVD) technique is a processing technique commonly used in the field of microelectronics, and for example, PVD may be used to process a copper interconnection layer in an integrated circuit. Fabrication of a copper interconnection layer mainly includes steps such as degassing, pre-cleaning, deposition of Ta(N), and deposition of Cu, where the step of degassing is for removing water vapor and other volatile impurities on a to-be-processed workpiece such as a substrate. When the step of degassing is implemented, a heating chamber needs to be utilized to heat the to-be-processed workpiece such as a substrate to a temperature above 300° C.
FIG. 1 is a structural schematic diagram of an existing beating chamber. Referring to FIG. 1, the heating chamber includes a barrel-shaped shielding member 3 and a reflection plate 2 disposed at the top thereof. Further, a sealed quartz window 9 is disposed inside the heating chamber, and via the sealed quartz window 9, the heating chamber is divided into an upper sub-chamber and a lower sub-chamber. The upper sub-chamber has an atmospheric environment, and the lower sub-chamber has a vacuum environment. Further, supporting pins 10 are configured at a bottom of the lower sub-chamber for bearing a substrate 4. Heating bulbs 6 are disposed inside the upper sub-chamber, and the heating bulbs 6 are fastened to a bulb installation plate 1 through bulb installation sockets 7. Further, the heating bulbs 6 are located below the reflection plate 2 to heat the substrate 4 by way of thermal radiation via the sealed quartz window 9. Further, a substrate transferring window 11 for transferring the substrate 4 into or out of the heating chamber is disposed in the shielding member 3.
In practical applications of the aforementioned heating chamber, the following issues inevitably exist.
First, because the heating bulbs 6 are arranged discretely, the heat radiated by the heating bulbs 6 to each area of the substrate 4 is not uniform, rendering uneven temperature in each area of the substrate 4, thereby causing the process to be non-uniform. Further, in the process of heating the substrate 4, because a marginal area of the substrate 4 is closer to the shielding member 3, a heat dissipation rate of the marginal area is higher than a heat dissipation rate of a central area of the substrate 4. Accordingly, a difference in the temperature exists between the central area and the marginal area of the substrate 4, which further lowers the processing uniformity.
Second, because each time the aforementioned heating chamber can only perform a degassing operation on limited a few substrates, and a relatively long time (nearly 200 seconds, which is four times a duration of a processing process such as a process for a copper barrier layer) is required, the number of substrates that can be processed per unit time is relatively small. Further, because the ratio occupied by the processing time of the step of degassing in the total processing time is the highest for certain PVD processes, the step of degassing becomes a key factor that limits the capacity of the whole PVD device. Accordingly, a beating chamber with high efficiency is currently highly desired to improve the capacity of the PVD device.